What is the actual formula this calculator uses?

GPA equals the sum of grade points times credit hours, added up across every course, divided by the sum of credit hours. A 4-credit class affects that total four times as much as a 1-credit class does. That ratio is what weighted means in this tool.

Why did switching from the 4.0 to the 4.5 scale change my GPA more than I expected?

Any A-, B-, C-, or D- grades you entered do not carry a minus-grade value on the 4.5 scale, because it has none. They collapse to the base letter instead, so an A- becomes an A, worth 4.0 on the 4.5 table rather than the 3.7 it was worth on the 4.0 scale. Re-check minus grades right after switching.

Does this calculator add bonus points for AP, IB, or Honors classes?

No. It weights by credit hours only, not by course level. If your school's official weighted GPA includes a level bonus, commonly plus 0.5 for Honors or plus 1.0 for AP or IB, you need to add that bonus to the grade point before entering it. The tool cannot tell which of your courses were AP versus standard on its own.

Can this calculator handle pass or fail grades or a retaken course correctly on its own?

Not automatically. There is no pass or fail grade option, so those courses, which usually do not count toward GPA, should be left off the list entirely. For a retaken course, check whether your school replaces or averages the old grade. The calculator will average both rows if you leave both in, which is only correct if that matches your school's actual policy.

I am applying abroad. Will my school's GPA match what the admissions office sees?

Not necessarily. Credential evaluators such as WES re-derive a US-equivalent GPA from your transcript using their own methodology rather than a simple linear scale conversion, and some scales, like the 4.3 scale a number of Korean universities use, are not identical to the 4.0 or 4.5 scales this tool implements. Treat this number as your own institution's figure, not a guaranteed admissions-office equivalent.

Does this tool upload my data?

No. Everything runs right in your browser, so your data never leaves your device — it even works offline once the page has loaded.

🎓 GPA Calculator

Your GPA is a weighted average, not a simple average: each course's grade point is multiplied by its credit hours before the total is divided by total credits, so a 3-credit class moves your GPA three times as much as a 1-credit one does. This calculator does that arithmetic for every course you add, on either the 4.0 scale most US schools use, where A and A+ both cap at 4.0, or the 4.5 scale most Korean universities use, where A+ equals 4.5 and there are no minus grades. Switch scales at any time; your entered grades remap automatically. It only computes what you type in. It cannot decide how your school treats retaken courses, pass or fail grades, or transfer credit, because those are policy questions, not math.

The GPA Calculator computes a credit-weighted grade point average from the letter grades and credit hours you enter, on either the 4.0 US scale or the 4.5 Korean university scale.

Add a course to get started.

Total Credits

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Weighted GPA

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Courses

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Grade → Points Reference

Private by design. This tool runs entirely in your browser — nothing you enter is uploaded or stored, and it works offline.

About

The formula behind every number this tool shows is: GPA equals the sum of grade points times credit hours, for every course, divided by the sum of credit hours. The word weighted here means weighted by credit hours per course. It does not mean the separate practice, common at US high schools, of adding bonus points for Honors, AP, or IB level courses. This calculator performs the credit-hour weighting only. It does not add level-based bonus points, so if your school's weighted GPA includes an AP or IB bonus, you need to add that bonus to the grade point yourself before entering it. The tool has no way to know which of your courses were AP versus standard.

Credit weighting changes the answer, and which direction it moves depends entirely on where the extreme grade happens to sit. Take a student with one A, worth 4.0, and one F, worth 0.0. If the A is in a 3-credit course and the F is in a 1-credit course, the credit-weighted GPA is (3 times 4.0, plus 1 times 0.0), divided by 4 credits, which is 12 divided by 4, or 3.00. That is noticeably better than the simple, credit-blind average of the two letter grades, which is (4.0 plus 0.0) divided by 2, or 2.00. Now flip which grade sits in the bigger course: a 3-credit F and a 1-credit A. The weighted GPA becomes (3 times 0.0, plus 1 times 4.0) divided by 4, which is 1.00, a full two points below that same simple average. Same two grades, same total credits, opposite outcomes. Which course happens to carry more credit decides whether weighting helps you or hurts you.

Scale choice changes the ceiling, not the underlying ranking. On the 4.0 scale, A+ and A are both worth 4.0; there is no reward for the plus. On the 4.5 scale, A+ is worth 4.5 and A is worth 4.0, so a straight-A+ transcript separates from a straight-A transcript in a way the 4.0 scale cannot show at all. Most Korean universities use the 4.5 scale, but a number of top schools, including Seoul National University, Yonsei, and Ewha, use a 4.3 scale instead, where A+ tops out at 4.3 rather than 4.5. This calculator implements 4.0 and 4.5 only, not 4.3, so check which scale your own transcript actually uses before comparing numbers.

Switching scales after you have already entered grades has one sharp edge case worth knowing about. Neither this tool's 4.5 table nor most Korean transcripts carry minus grades: there is no A-, B-, C-, or D- tier on the 4.5 scale. If you enter an A- on the 4.0 scale, worth 3.7, and then switch to 4.5, the calculator does not invent a 4.5-scale minus value for it. It collapses the grade down to the base letter A, which is worth 4.0 on the 4.5 table, not 4.5 and not the 3.7 it was worth a moment ago. That is a real drop from what the A- was worth on the 4.0 scale, not an upgrade, so re-check every minus grade after switching scales rather than assuming the number carried over unchanged.

Where this stops being reliable, in ways that are policy questions rather than arithmetic errors: the calculator has no concept of your school's retake rules. If you retook a class and your school replaces the old grade rather than averaging it, you have to delete the old attempt yourself, because leaving both rows in will always pull your GPA toward whichever grade was worse, which is wrong if your school only counts the retake. There is no pass or fail grade option, so pass or fail courses, which typically do not count toward GPA at all, need to be left off the list entirely rather than entered with a placeholder letter grade. The tool also does not know whether your institution counts transfer credit hours toward your cumulative GPA; many count the credit hours earned but not the grade itself, and entering a transfer course here folds its grade into the average regardless of that policy. In every one of these cases, the number the tool displays is arithmetically correct for the rows you typed in. The judgment call about which rows belong in the list at all is yours, and it depends on your specific school's academic regulations, not on GPA math.

If you are using this GPA for a study-abroad or graduate application outside your home country, one more gap is worth flagging. Credential evaluation services such as WES do not simply take your school's reported number. They re-derive a US-equivalent GPA from your raw transcript using their own course-by-course methodology, which can land meaningfully above or below what a simple linear conversion between scales would suggest. Treat the number this calculator shows as what your home institution would print on your own transcript, not as a guaranteed stand-in for whatever a foreign credential evaluator ultimately reports.

How to use

Pick your grading scale first, 4.0 US or 4.5 Korean university, since it changes what each letter grade is worth, especially at the top end.
Click Add course for every class you want counted, and set its credit hours. This is what makes the average weighted rather than a flat mean of letter grades.
Set each course's letter grade from the dropdown. The point value and a color-coded points figure update immediately for that row.
Read the cumulative weighted GPA, total credits, and course count at the top of the page. All three update live as you add or edit rows.
If you need to switch scales after entering grades, re-check any minus grades afterward. The tool remaps them automatically, but a minus grade collapses to its base letter rather than gaining a new minus-tier value.

FAQ

What is the actual formula this calculator uses?: GPA equals the sum of grade points times credit hours, added up across every course, divided by the sum of credit hours. A 4-credit class affects that total four times as much as a 1-credit class does. That ratio is what weighted means in this tool.
Why did switching from the 4.0 to the 4.5 scale change my GPA more than I expected?: Any A-, B-, C-, or D- grades you entered do not carry a minus-grade value on the 4.5 scale, because it has none. They collapse to the base letter instead, so an A- becomes an A, worth 4.0 on the 4.5 table rather than the 3.7 it was worth on the 4.0 scale. Re-check minus grades right after switching.
Does this calculator add bonus points for AP, IB, or Honors classes?: No. It weights by credit hours only, not by course level. If your school's official weighted GPA includes a level bonus, commonly plus 0.5 for Honors or plus 1.0 for AP or IB, you need to add that bonus to the grade point before entering it. The tool cannot tell which of your courses were AP versus standard on its own.
Can this calculator handle pass or fail grades or a retaken course correctly on its own?: Not automatically. There is no pass or fail grade option, so those courses, which usually do not count toward GPA, should be left off the list entirely. For a retaken course, check whether your school replaces or averages the old grade. The calculator will average both rows if you leave both in, which is only correct if that matches your school's actual policy.
I am applying abroad. Will my school's GPA match what the admissions office sees?: Not necessarily. Credential evaluators such as WES re-derive a US-equivalent GPA from your transcript using their own methodology rather than a simple linear scale conversion, and some scales, like the 4.3 scale a number of Korean universities use, are not identical to the 4.0 or 4.5 scales this tool implements. Treat this number as your own institution's figure, not a guaranteed admissions-office equivalent.
Does this tool upload my data?: No. Everything runs right in your browser, so your data never leaves your device — it even works offline once the page has loaded.